How do you calculate incremental rainfall?

1. Cumulative fraction – interpolate SCS table.
2. Cumulative rainfall = product of cumulative fraction * total 24-hour rainfall (10.01 in)
3. Incremental rainfall = difference between current and preceding cumulative rainfall.

What is a rainfall hyetograph?

A hyetograph is a graphical representation of the distribution of rainfall intensity over time.

What is type II rainfall distribution?

NRCS Standard Type II and Type III Distributions The Type II pattern distributes 45 percent of the total 24-hour rainfall in the maximum one-hour while the Type III pattern distributes 40 percent of the total rainfall in the maximum one-hour.

How do you calculate rainfall distribution?

By calculating the product of the rainfall intensity and the duration (i.e., the rainfall depth) for each rainfall duration, the cumulative rainfall distribution can be derived. The rainfall intensity data can then be obtained as the difference between the successive cumulative rainfall depths.

What is hyetograph and hydrograph?

A hydrograph is graphically plot of discharge of a natural system for river versus time. A hyetograph is a plot of intensity of rainfall against the time interval it is usually represented buy a bar chart.

What is SCS rainfall distribution?

The SCS Rainfall Method was developed by the United States Department of Agriculture – Natural Resources Conservation Service (USDA-NRCS). It generated four synthetic 24-hour rainfall distribution curves that cover all geographical regions of the United States.

What is SCS distribution?

The SCS 24-hr. rainfall distributions are classic examples of dimensionless depth rainfall distributions. The Y-axis is dimensionless so that different rainfall depths can be applied to the distributions to create rainfall curves for various storm magnitudes and geographic locations.

What is rainfall distribution?

Rainfall pattern means the distribution of rain geographically, temporally, and seasonally. The tropics receive more rainfall than deserts. Cooler places like the poles receive no rainfall, as it is converted to snow before it falls to the ground.

What is the full form of IDF curve?

An intensity-duration-frequency curve (IDF curve) is a mathematical function that relates the rainfall intensity with its duration and frequency of occurrence. These curves are commonly used in hydrology for flood forecasting and civil engineering for urban drainage design.

What is the unit of hyetograph?

Unit hydrograph is a direct runoff hydrograph resulting from one unit (one inch or one cm) of constant intensity uniform rainfall occurring over the entire watershed. The concept of unit hydrograph is based on linear systems theory and follow the principles of superposition and proportionality.

What unit is CSM?

Abbreviated csm. Curve number A dimensionless number of 98 or less that relates runoff to the soil-cover complex of a watershed. The curve number indicates the runoff potential of a soil-cover complex during periods when the soil is not frozen.

What is synthetic rainfall distribution?

A synthetic rainfall curve is a plot of rainfall depth versus time that can be used in lieu of actual rainfall event data. A synthetic rainfall distribution is useful because it incorporates maximum rainfall intensities for a given event frequency arranged in a sequence that produces peak runoff.